A patient with a secondary prevention ICD in situ experienced a shock from his device. The download is shown in the strip. It is a single-chamber device and the top trace is from the RV tip to RV ring and the lower trace is from the generator can to the RV shock coil.
This is a single-chamber device and it is important not to become confused and think that the top trace is from an atrial lead and that the diagnosis is AF. The rate is very fast and irregular with a chaotic morphology demonstrating VF. ATP would have been unsuccessful, but a further clue that this was a shock comes from the notation 24.9J at the bottom of the strip at the point the shock was delivered. Different manufacturers’ interrogation strips can look quite different but close scrutiny of all the information can often give the answer.
A 65-year-old diabetic man with a previous history of myocardial infarction 3 years ago (no intervention required) is found to have atrial fibrillation. His LVEF is 55% and he has no cardiovascular symptoms. What would you advise him with regard to the best thromboprophylaxis?
This man has a CHADS2 score of 1 (one point for diabetes) and therefore could be offered warfarin or aspirin thromboprophylaxis according to this risk stratification system. However, if the newer CHA2DS2-VASc system is used, he has a score of 3 ( one point for each of DM, age 65–74, and previous MI) and should be offered oral anticoagulation (warfarin or newer agents). A CHA2DS2-VASc score of zero is truly low risk and could be managed with no thromboprophylaxis at all or aspirin (no thromboprophylaxis preferable). A CHA2DS2-VASc score of 1 could be managed with aspirin or oral anticoagulation (the latter is preferable). A score ≥2 should be managed with oral anticoagulation. In summary oral anticoagulation is preferred to aspirin in AF patients with one or more stroke risk factors based on the CHA2DS2-VASc score. In the absence of recent ACS or coronary artery stenting, there is no good evidence for either warfarin or antiplatelet drugs.
A 25-year-old man presents to the ED with a broad complex tachycardia that is irregularly irregular. The patient is haemodynamically uncompromised. An anaesthetist is not available to assist with immediate DC cardioversion. What is the best initial treatment option?
This man may have an accessory pathway with rapidly conducted AF. Adenosine, digoxin, verapamil, and beta-blockers should all be avoided as they prolong the AV node refractory period and thus may increase conduction down an accessory pathway. This increases the risk of rapidly conducted AF becoming VF. Intravenous class I antiarrhythmic drugs (e.g. procainamide, flecainide, propafenone) can be used as well as amiodarone, but DC cardioversion is the treatment of choice if there is haemodynamic compromise or rapidly conducted AF down an accessory pathway.
A 60-year-old man attends clinic because of hypertension. His BP in clinic is 70/90 mmHg and his echocardiogram shows mild LVH and mild LA dilatation. He is not diabetic and has no other medical history of note. Which one of the following medications is most effective in preventing AF?
. ACE inhibitors and ARBs have antifibrillatory and antifibrotic properties. A meta-analysis has shown that ACE inhibitors and angiotensin-receptor blockers (ARBs) reduce the relative risk of incident AF by 25%. The LIFE study, in particular, showed a 33% reduction in new-onset AF in patients with LVH treated with losartan compared with those treated with atenolol.
A 62-year-old woman attends clinic following an ED attendance 6 weeks previously with a one-week history of palpitations. She was diagnosed with AF at the time and commenced on aspirin and a beta-blocker. Her echocardiogram showed no significant abnormalities and her ECG in clinic today confirms atrial fibrillation with a ventricular rate of 70 bpm. She continues to get occasional palpitations and would like to be considered for cardioversion. What do you advise?
Patients should be anticoagulated with a therapeutic INR (>2) for at least 3 weeks prior to cardioversion. Anticoagulation should be continued for at least 4 weeks post-cardioversion as ‘atrial stunning’ may occur. Anticoagulation is required prior to both chemical and electrical cardioverison. If a patient has not had oral anticoagulation for at least 3 weeks, it is reasonable to perform DC cardioversion if a TOE rules out left atrial thrombus. However, LMWH should be commenced prior to a TOE-guided cardioversion and continued post-cardioversion until the target INR is reached with oral anticoagulation.
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